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Tone (linguistics)

Tone is the use of pitch in language to distinguish lexical or grammatical meaning—that is, to distinguish or inflect words. All languages use pitch to express emotional and other paralinguistic information, and to convey emphasis, contrast, and other such features in what is called intonation, but not all languages use tones to distinguish words or their inflections, analogously to consonants and vowels. Such tonal phonemes are sometimes called tonemes.

A slight majority of the languages in the world are tonal. However, most Indo-European languages, which include the most widely spoken languages in the world today, are not tonal.

In the most familiar tonal language, Chinese, tones are distinguished by their shape (contour), most syllables carry their own tone, words tend to be short, and many words are differentiated solely by tone. (This is more true in Cantonese than Mandarin.) Tone also plays almost no grammatical role. In many African tone languages, such as most Bantu languages, however, tones are distinguished by their relative level, words are longer, there are fewer minimal tone pairs, and a single tone may be carried by the entire word, rather than a different tone on each syllable. Often grammatical information, such as past versus present, "I" versus "you", or positive versus negative, is conveyed solely by tone.

Many languages use tone in a more limited way. Somali, for example, may only have one high tone per word. In Japanese, less than half of the words have drop in pitch; words contrast according to which syllable this drop follows. Such minimal systems are sometimes called pitch accent, since they are reminiscent of stress accent languages which typically allow one principal stressed syllable per word. However, the term "pitch accent" does not have a coherent definition.

Tonal languages

Languages that are tonal include:

Some of the Sino-Tibetan languages, including the numerically most important ones. Most forms of Chinese are strongly tonal (an exception being Shanghainese, where the system has collapsed to only a two-way contrast at the word level with some initial consonants, and no contrast at all with others); while some of the Tibetan languages, including the standard languages of Lhasa and Bhutan and Burmese are more marginally tonal. However, Nepal Bhasa, the original language of Kathmandu, is non-tonal, as are several Tibetan dialects and many other Tibeto-Burman languages.

Many Afro-Asiatic languages in the Chadic, Cushitic and Omotic families have register-tone systems, such as Chadic Hausa. Many of the Omotic tone systems are quite complex. However, many other languages in these families, such as the Cushitic language Somali, have minimal tone.

Slightly more than half of the Athabaskan languages, such as Navajo, have simple register-tone systems (languages in California, Oregon and a few in Alaska excluded), but the languages that have tone fall into two groups that are mirror images of each other. That is, a word which has a high tone in one language will have a cognate with a low tone in another, and vice versa.

All Oto-Manguean languages are tonal. Most have register-tone systems, some contour systems. These are perhaps the most complex tone systems in America.

The vast majority of Austronesian languages are non-tonal, but a small number have developed tone. No tonal language has been reported from Australia. With other languages we simply don't know. For example, the Ket language has been described as having up to eight tones by some investigators, as having four tones by others, but by some as having no tone at all. In cases such as these, the classification of a language as tonal may depend on the researcher's interpretation of what tone is. For instance, the Burmese language has phonetic tone, but each of its three tones is accompanied by a distinctive phonation (creaky, murmured or plain vowels). It could be argued either that the tone is incidental to the phonation, in which case Burmese would not be phonemically tonal, or that the phonation is incidental to the tone, in which case it would be considered tonal. Something similar appears to be the case with Ket.

A famous example of tone in Ancient Greek comes from Aristophanes' Frogs, where (l. 304) Aristophanes mentions an instance at a performance of Euripides' play Orestes, where an actor pronounced galḗn' horō "I see calm waters" with so much empathy that it came out galên horō "I see a weasel".

Tone as a distinguishing feature

Most languages use pitch as intonation to convey prosody and pragmatics, but this does not make them tone languages. In tone languages, tone is phonemic, and thus minimal pairs distinguished by tone exist in such languages.

Here is a minimal tone set from Mandarin Chinese, which has five tones, here transcribed by diacritics over the vowels:

A high level tone: /á/ (pinyin )

A tone starting with mid pitch and rising to a high pitch: /ǎ/ (pinyin )

A low tone which dips briefly before, if there is no following syllable, rising a high pitch: /à/ (pinyin )

A sharply falling tone, starting high and falling to the bottom of the speaker's vocal range: /â/ (pinyin )

A neutral tone, sometimes indicated by a dot (·) in Pinyin, has no specific contour; its pitch depends on the tones of the preceding and following syllables. Mandarin speakers refer to this tone as the "light tone" (輕聲).

These tones combine with a syllable such as "ma" to produce different words. A minimal set based on "ma" are, in pinyin transcription,

Register tones and contour tones

Most Chinese languages use contour tone systems, where the distinguishing feature of the tones are their shifts in pitch (that is, the pitch is a contour), such as rising, falling, dipping, or level. Most Bantu languages, on the other hand, have register tone systems, where the distinguishing feature is the relative difference between the pitches, such as high, mid, or low, rather than their shapes. In many register tone systems there is a default tone, usually low in a two-tone system or mid in a three-tone system, that is more common and less salient than other tones. There are also languages that combine register and contour tones, such as many Kru languages, where nouns are distinguished by contour tones and verbs by register. Others, such as Yoruba, have phonetic contours, but these can easily be analysed as sequences of register tones, with for example sequences of high–low /áà/ becoming falling [âː], and sequences of low–high /àá/ becoming rising [ǎː].

Register languages

The term "register", when not used in the phrase "register tone", commonly indicates vowel phonation combined with tone in a single phonological system. Burmese, for example, is a register language, where differences in pitch are so intertwined with vowel phonation that neither can be considered without the other.

Tone terracing and tone sandhi

Tones are realized as pitch only in a relative sense. 'High tone' and 'low tone' are only meaningful relative to the speaker's vocal range and in comparing one syllable to the next, rather than as a contrast of absolute pitch such as one finds in music. As a result, when one combines tone with sentence prosody, the absolute pitch of a high tone at the end of a prosodic unit may be lower than that of a low tone at the beginning of the unit, because of the universal tendency (in both tonal and non-tonal languages) for pitch to decrease with time in a process called downdrift.

Tones may affect each other just as consonants and vowels do. In many register-tone languages, low tones may cause a downstep in following high or mid tones; the effect is such that even while the low tones remain at the lower end of the speaker's vocal range (which is itself descending due to downdrift), the high tones drop incrementally like steps in a stairway or terraced rice fields, until finally the two merge and the system has to be reset. This effect is called tone terracing.

Sometimes a tone may remain as the sole realization of a grammatical particle after the original consonant and vowel disappear, so it can only be heard by its effect on other tones. It may cause downstep, or it may combine with other tones to form contours. These are called floating tones.

In many contour-tone languages, one tone may affect the shape of an adjacent tone. The affected tone may become something new, a tone that only occurs in such situations, or it may be changed into a different existing tone. This is called tone sandhi. In Mandarin Chinese, for example, a dipping tone between two other tones is reduced to a simple low tone, which otherwise does not occur in Mandarin, whereas if two dipping tones occur in a row, the first becomes a rising tone, indistinguishable from other rising tones in the language.

Word tones and syllable tones

Another difference between tonal languages is whether the tones apply independently to each syllable or to the word as a whole. In Cantonese, Thai, and to some extent the Kru languages, each syllable may have any tone, whereas in Shanghainese, the Scandinavian languages, and many Bantu languages, the contour of each tone operates at the word level. That is, a trisyllabic word in a three-tone syllable-tone language has many more tonal possibilities (3×3×3=27) than a monosyllabic word (3), but there is no such difference in a word-tone language. For example, Shanghainese has two contrastive tones no matter how many syllables are in a word. Many languages described as having pitch accent are word-tone languages.

Tone sandhi is an intermediate situation, as tones are carried by individual syllables, but affect each other so that they are not independent of each other. For example, a number of Mandarin suffixes and grammatical particles have what is called (when describing Mandarin) a "neutral" tone, which has no independent existence. If a syllable with a neutral tone is added to a syllable with a full tone, the pitch contour of the resulting word is entirely determined by that other syllable:

Realization of neutral tones in Mandarin

Tone in isolation

Tone pattern withadded 'neutral tone'

Example

Pinyin

English meaning

high ˥

˥.˨

玻璃

bōli

glass

rising ˧˥

˧˥.˧

伯伯

bóbo

uncle

dipping ˨˩˦

˨˩.˦

喇叭

lǎba

horn

falling ˥˩

˥˩.˩

兔子

tùzi

rabbit

After high level and high rising tones, the neutral syllable has an independent pitch that looks like a mid register tone the default tone in most register-tone languages. However, after a falling tone it takes on a low pitch; the contour tone remains on the first syllable, but the pitch of the second syllable matches where the contour leaves off. And after a low-dipping tone, the contour spreads to the second syllable: The contour remains the same (˨˩˦) whether the word has one syllable or two. In other words, the tone is now the property of the word, not the syllable. Shanghainese has taken this pattern to its extreme, as the pitches of all syllables are determined by the tone before them, so that only the tone of the initial syllable of a word is distinctive.

Notational systems

Due to the fact that tonal languages are found all over the world, several systems to mark tone have developed independently. In Asian and Meso-American contexts, numerical systems are most common, whereas IPA-style diacritic marks are used mainly in African contexts. Because of font-support issues, the International Phonetic Alphabet is not commonly used for complex contour tone systems; see under Chinese below for one work-around.

Africa

In African linguistics (as well as in many African orthographies), usually a set of accent marks is used to mark tone. The most common phonetic set (which is also included in the International Phonetic Alphabet) is found below:

High tone

acute

á

Mid tone

macron

ā

Low tone

grave

à

Several variations are found. In many three tone languages, it is common to mark High and Low tone as indicated above, but to omit marking of the Mid tone, e.g., má (High), ma (Mid), mà (Low). Similarly, in some two tone languages, only one tone is marked explicitly.

With more complex tonal systems, such as in the Kru and Omotic languages, it is usual to indicate tone with numbers, with 1 for HIGH and 4 or 5 for LOW. Contour tones are then indicated 14, 21, etc.

Asia

In the Chinese tradition, numerals are assigned to various tones. For instance, Standard Mandarin has five tones, and the numerals 1, 2, 3, and 4 are assigned to four tones, and the neutral tone is left numberless. Chinese dialects are traditionally described in terms of eight tones (six tones, from the perspective of modern linguistics), though many dialects do not have all of them. Outside standard Mandarin, the numerals 1 to 8 are assigned to these tones based on their historical origin. In neither of these systems does the numeral have anything to do with the pitch values of the tones. Tone 5, for example, has drastically different realizations in different dialects.

More iconic systems are to use tone numbers, or an equivalent set of graphic pictograms known as 'Chao tone letters'. These divide the pitch into five levels, with the lowest being assigned the value 1, and the highest the value 5. (This is the opposite of equivalent systems in Africa and the Americas.) The variation in pitch of a tone contour is notated as a string of two or three numbers. For instance, the four Mandarin tones are transcribed as follows (note that the tone letters will not display properly unless you have a compatible font installed):

Tones of Standard Mandarin

High tone

55

˥˥

(Tone 1)

Mid rising tone

35

˧˥

(Tone 2)

Low dipping tone

214

˨˩˦

(Tone 3)

High falling tone

51

˥˩

(Tone 4)

A mid-level tone would be indicated by /33/, a low level tone /11/, etc.

Standard IPA notation is also sometimes seen for Chinese. One reason it is not more widespread is that only two contour tones, rising /ɔ̌/ and falling /ɔ̂/, are widely supported by IPA fonts, while several Chinese languages have more than one rising or falling tone. One common work-around is to retain standard IPA /ɔ̌/ and /ɔ̂/ for high-rising (/35/) and high-falling (/53/) tones, and to use the subscript diacritics /ɔ̗/ and /ɔ̖/ for low-rising (/13/) and low-falling (/31/) tones.

The Thai language has five tones: high, mid, low, rising and falling. It uses an alphabetic writing system which specifies the tone unambiguously. Tone is indicated by an interaction of the initial consonant of a syllable, the vowel, the final consonant (if present), and sometimes a tone mark. A particular tone mark may denote different tones depending on the initial consonant.

Vietnamese uses the Latin alphabet, and the 6 tones are marked by diacritics above or below a certain vowel of each syllable. In many words that end in diphthongs, however, exactly which vowel is marked is still debatable. Notation for Vietnamese tones are as follows:

The Latin-based Hmong and Iu Mien alphabets use full letters for tones. In Hmong, one of the eight tones (the ˧ tone) is left unwritten, while the other seven are indicated by the letters b, m, d, j, v, s, g at the end of the syllable. Since Hmong has no phonemic syllable-final consonants, there is no ambiguity. This system enables Hmong speakers to type their language with an ordinary Latin-letter typewriter without having to resort to diacritics. In the Iu Mien, the letters v, c, h, x, z indicate tones but, unlike Hmong, it also has final consonants written before the tone.

The Japanese language does not have tone, but does have downstep, so that 雨 áme (rain), with a drop in pitch after the first syllable, is distinguished from あめ ame (candy), which has no drop.

The Americas

Several North American languages have tone, one of which is Oklahoma Cherokee, said to be the most musical of the Iroquoian languages. Cherokee has six tones (1 low, 2 medium, 3 high, 4 very high, 23 rising and 32 falling).

In Mesoamericanist linguistics, /1/ stands for High tone and /5/ stands for Low tone. It is also common to see acute accents for high tone and grave accents for low tone and combinations of these for contour tones. Several popular orthographies use ‹j› or ‹h› after a vowel to indicate low tone.

A number of languages of South America are tonal. For example, the Pirahã language has three tones. The Ticuna language isolate is exceptional for having five level tones (the only other languages to have such a system are the Trique language and the Usila dialect of Chinantec (both Oto-Manguean languages of Mexico).

Europe

Both Swedish and Norwegian have a phenomenon that is often called "tone", but it is better understood as a pitch accent, as it appears only in words of two or more syllables. (Tones, according to the linguistic definition, are found on every syllable in tone languages.) This pitch accent is mostly used prosodically, but also to differentiate two-syllable words depending on their morphological structure. These accents are usually referred to as accent 1 and accent 2 (or acute accent and grave accent), respectively. For further explanation and examples, see the Swedish and Norwegian language articles.

Number of tones

Languages may distinguish up to five levels of pitch, though it is possible that the Chori language of Nigeria distinguishes six. Since tone contours may involve up to two shifts in pitch, there are theoretically 5*5*5 = 125 distinct tones. However, the most that are used in any one language is a tenth that number.

If we include contour tones as separate tones, several Kam-Sui languages of southern China have nine tones, assuming that final consonants are not counted as additional tones, as they traditionally are in China. One of them, Ai-Cham (錦話), is said to have eleven tones.

Preliminary work on the Wobe language of Liberia and Ivory Coast and the Chatino languages of southern Mexico suggests that some dialects may distinguish as many as fourteen tones, but many linguists have expressed doubts, believing that many of these will turn out to be sequences of two tones.

Tonal Consonants

Tone is often carried by the syllable, so syllabic consonants such as nasals and trills may bear tone. This is especially common with syllabic nasals, for example in many Bantu and Kru languages.

Origin of tone

The historical origin of tone is called tonogenesis. Tone is frequently an areal rather than a genealogical feature: That is, a language may acquire tones through bilingualism if influential neighboring languages are tonal, or if speakers of a tonal language shift to the language in question, and bring their tones with them. In other cases, tone may arise spontaneously, and surprisingly quickly: The dialect of Cherokee in Oklahoma has tone, but the dialect in North Carolina does not, although they were only separated in 1838.

Very often, tone arises as an effect of the loss or merger of consonants. (Such trace effects of disappeared sounds, which is not restricted to tone, have been nicknamed Cheshirisation, after the lingering smile of the disappearing Cheshire cat in Alice in Wonderland.) In a non-tonal language, voiced consonants commonly cause following vowels to be pronounced at a lower pitch than other consonants do. This is usually a minor phonetic detail of voicing. However, if consonant voicing is subsequently lost, that incidental pitch difference may be left over to carry the distinction that the voicing had carried, and thus becomes meaningful (phonemic). We can see this historically in Panjabi: the Panjabi murmured (voiced aspirate) consonants have disappeared, and left tone in their wake. If the murmured consonant was at the beginning of a word, it left behind a high tone; if at the end, a high tone. If there was no such consonant, the pitch was unaffected; however, the unaffected words are limited in pitch so as not to interfere with the low and high tones, and so has become a tone of its own: mid tone. The historical connection is so regular that Panjabi is still written as if it had murmured consonants, and tone is not marked: The written consonants tell the reader which tone to use.

Similarly, final fricatives or other consonants may phonetically affect the pitch of preceding vowels, and if they then weaken to /h/ and finally disappear completely, the difference in pitch, now a true difference in tone, carries on in their stead. This was the case with the Chinese languages: Two of the three tones of Middle Chinese, the "rising" and "leaving" tones, arose as the Old Chinese final consonants /ʔ/ and disappeared, while syllables that ended with neither of these consonants were interpreted as carrying the third tone, "even". Most dialects descending from Middle Chinese were further affected by a tone split, where each tone split in two depending on whether the initial consonant was voiced: Vowels following an unvoiced consonant acquired a higher tone while those following a voiced consonant acquired a lower tone as the voiced consonants lost their distinctiveness.

The same changes affected many other languages in the same area, and at around the same time (AD 1000–1500). The tone split, for example, also occurred in Thai, Vietnamese, and the Lhasa dialect of Tibetan.

In general, voiced initial consonants lead to low tones, while vowels after aspirated consonants acquire a high tone. When final consonants are lost, a glottal stop tends to leave a preceding vowel with a high or rising tone (although glottalized vowels tend to be low tone, so if the glottal stop causes vowel glottalization, that will tend to leave behind a low vowel), whereas a final fricative tends to leave a preceding vowel with a low or falling tone. Vowel phonation also frequently develops into tone, as can be seen in the case of Burmese.

Tone arose in the Athabascan languages at least twice, in a patchwork of two systems. In some languages, such as Navajo, syllables with glottalized consonants (including glottal stops) in the syllable coda developed low tones, whereas in others, such as Slavey, they developed high tones, so that the two tonal systems are almost mirror images of each other. Syllables without glottalized codas developed the opposite tone—for example, high tone in Navajo and low tone in Slavey, due to contrast with the tone triggered by the glottalization. Other Athabascan languages, namely those in western Alaska (such as Koyukon) and the Pacific coast (such as Hupa), did not develop tone. Thus, the Proto-Athabascan word for "water" *tuː is toneless toː in Hupa, high-tone tó in Navajo, and low-tone tù in Slavey; while Proto-Athabascan *-ɢʊtʼ "knee" is toneless -ɢotʼ in Hupa, low-tone -ɡòd in Navajo, and high-tone -góʼ in Slavey. Kingston (2005) provides a phonetic explanation for the opposite development of tone based on the two different ways of producing glottalized consonants with either (a) tense voice on the preceding vowel, which tends to produce a high F0, or (b) creaky voice, which tends to produce a low F0. Languages with "stiff" glottalized consonants and tense voice developed high tone on the preceding vowel and those with "slack" glottalized consonants with creaky voice developed low tone.

The Bantu languages also have "mirror" tone systems, where the languages in the northwest corner of the Bantu area have the opposite tones of other Bantu languages.

Three Algonquian languages developed tone independently of each other and of neighboring languages: Cheyenne, Arapaho, and Kickapoo. In Cheyenne, tone arose via vowel contraction; the long vowels of Proto-Algonquian contracted into high-pitched vowels in Cheyenne, while the short vowels became low-pitched. In Kickapoo, a vowel with a following [h] acquired a low tone, and this tone later extended to all vowels followed by a fricative.

Pike, Kenneth L. (1948). Tone languages: A technique for determining the number and type of pitch contrasts in a language, with studies in tonemic substitution and fusion. Ann Arbor: The University of Michigan Press. (Reprinted 1972, ISBN 0-472-08734-7).